Aiken-Augusta region under air advisory today

The Augusta-Aiken area joins metro Atlanta today as one of several cities across the Southeast under a health advisory for rising levels of air pollution.

In this range the outdoor air is likely to be unhealthy for some people, said the orange advisory, issued by Georgias Environmental Protection Division through the U.S. Environmental Protection Agencys air quality forecasting Web site.

Children, people who are sensitive to ozone, and people with heart or lung disease should limit prolonged outdoor exertion during the late afternoon or early evening when ozone concentrations are highest, the advisory said.

The primary concern is ground-level ozone, which is formed by chemical reactions of nitrogen oxides and hydrocarbons, also called volatile organic compounds. They are produced when fuels such as gas or coal are burned or when chemicals evaporate. They combine with heat and sunlight to form smog.

The advisory does not mean Augusta will exceed the federal standards for ozone today, but levels could approach the violation mark and reach levels that are unhealthy for sensitive residents.

Metro Atlanta has already recorded six days this year in which levels exceeded federal standards, but Augusta has no violations so far.

Augusta recorded four violations in 2008, three in 2007, four in 2006 and one in 2005.

The number of violations, however, could potentially increase this summer, even if the air in Augusta is no dirtier than in past years. The reason is a new federal ozone standard unveiled last year that reduced the allowable concentration in the air to no more than 0.075 parts per million - the old standard was 0.085.

When pollution levels hit the orange level, operators of camps and daycare centers for young children should also take some precautions, according to Rebecca Watts Hull, manager of the Georgia Conservancys Mothers and Others for Clean Air Program.

Adjusting outdoor activities might be warranted on days when ozone  or another form of pollution known as particulate  approach or exceed federal guidelines.

Although ozone levels predictably peak between 2 p.m. and 7 p.m., particle pollution levels can remain high all day, she said.

Day-care and camp operators are also encouraged to check real-time pollution monitors, rather than relying solely on weather forecasts or predictions.

Outdoor play is important and childhood obesity is a serious public health issue in Georgia, so we want to help child caregivers avoid keeping kids indoors unnecessarily, she said.

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Todays weather will be hot, and tomorrow will be even hotter, according to the National Weather Service.

Todays forecast calls for a chance of showers and thunderstorms, with a high of about 96 and heat index values as high as 101. Saturdays forecast calls for more of the same, but with a high of 98 degrees and heat index values of 103.

Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earths upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found:

Good Ozone. Ozone occurs naturally in the Earths upper atmosphere 6 to 30 miles above the Earths surface, where it forms a protective layer that shields us from the suns harmful ultraviolet rays. Manmade chemicals are known to destroy this beneficial ozone. EPA has established regulations to phase out ozone-depleting chemicals in the United States.

Bad Ozone. In the Earths lower atmosphere, near ground level, ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the presence of sunlight. Ozone at ground level is a harmful air pollutant.